Device for protecting an electronic system mounted in a rack

ABSTRACT

Device for protecting an electronic system, comprising a case ( 2 ) intended to receive the electronic system and to be mounted in a rack ( 3 ) of a storage system ( 1 ) that can receive a number of cases ( 2 ), said metallic case ( 2 ) comprising a first opening ( 5 ) situated on a first of its faces, a second opening on a second of its faces, and a cooling system ( 8 ) comprising a duct linking the openings ( 5 ). 
     The wall of the duct is air-tight.

This application claims priority to French application No. FR 1057503, filed Sep. 20, 2010, the entire disclosure of which is incorporated herein by this reference.

The invention relates to the protection of electronic systems, in particular electronic systems contained in cases mounted in racks of a storage system.

The current cases are linked to an external cooling system which, in the event of a failure, requires all of the cases mounted in racks of one and the same storage system to be taken out of service or to adopt a degraded operating mode. The performance levels of an electronic system contained in such a case are reduced, and the availability of the electronic system becomes zero or very low.

Thus, it is necessary to use several redundant cooling systems or several redundant electronic systems.

In the event of a serious malfunction, a fire may start or smoke may appear within the electronic system. The cooling systems, using forced air convection, are likely to add a significant quantity of oxygen which sustains the flames and may represent a risk of the flames spreading to the other electronic systems contained in other, adjacent cases.

It is therefore necessary to contain the smoke inside the case and to prevent the provision of oxygen to an electronic system when a fire starts.

The cases currently used also offer low protection against the electromagnetic interference emitted or received by the electronic systems.

Reference can be made to the document FR 2 910 779, which describes a case of an electronic system which uses a cooling system based on natural and forced convection. The case contains a set of internal and external radiators suitable for complementing the cooling in the event of a fan failure.

The international application WO 2010/028384 describes a case of an electronic system comprising a hot air exhaust duct. The case also comprises fans to obtain a forced convection.

Reference can also be made to the document WO 2005/074345 which describes a case of an electronic system which comprises a cooling system incorporated in the case. This cooling system comprises a fan and a heat exchanger. The walls of the case are equipped with louvres suitable for allowing air to enter in the event of a failure of the in-built cooling system.

The cases described in these documents do not make it possible to contain the smoke or to prevent the provision of oxygen in the event of a start of a fire.

The aim of the invention is therefore to resolve the abovementioned drawbacks, and in particular, to propose a device for protecting an electronic system suitable for containing the smoke inside the device and for preventing the provision of oxygen in the event of the start of a fire.

The aim of the invention is also to propose a stand-alone cooling system for each case mounted in a rack of a storage system that can receive several cases.

Another aim of the invention is to provide a forced convection that is effective and robust to the failure of a fan.

The subject of the invention is therefore a device for protecting an electronic system, comprising a case intended to receive the electronic system and to be mounted in a rack of a storage system that can receive several cases. The case comprises a first opening situated on a first of its faces, a second opening on a second of its faces, and a cooling system comprising a duct linking the openings.

The wall of the duct is at least partly air-tight.

The air-tight duct makes it possible to cool the electronic system without providing oxygen directly to this electronic system. Furthermore, the start of a fire cannot spread to the other cases and the smoke is contained.

Advantageously, the case is metallic.

The use of a metallic case makes it possible to obtain a protection against the electromagnetic interference emitted and received by the electronic system.

Furthermore, the cooling system comprises a first fan associated with the first opening and second fan associated with the second opening.

The cooling system therefore uses a forced convection likely to maintain a ventilation in the event of the failure of one of the two fans.

The cooling system comprises heat dissipation means situated between the first fan and the second fan.

The electronic system can be linked to the case by a support suitable for dissipating the power lost by the electronic system.

Thus, the power lost by the system is extracted by a heat transfer by conduction before the cooling system removes it through a transfer by convection.

The cooling system can be linked to an air extraction system.

The air extraction system makes it possible to recover the hot air output from a number of cases, each having a stand-alone cooling system, and not to heat up the surrounding air.

Advantageously, the flow of air passing through the cooling system circulates from the first opening to the second opening or from the second opening to the first opening.

The first face can be the accessible face of the case, or front face, and the second face is the rear face of the case.

As a variant, the first face is the bottom face of the case, and the second face is the top face of the case.

Because of this, when the ease is stored vertically in a rack, the air circulates between the faces that are not up against the faces of an adjacent case.

According to another embodiment, the device comprises, on the first face two openings, on the second face two openings, and two cooling systems each comprising a duct linking the openings of the first face to the openings of the second face.

Other aims, features and advantages of the invention will become apparent from reading the following description, given solely as a nonlimiting example, and with reference to the appended drawings in which:

FIG. 1 represents a perspective view of a storage system in which a number of cases according to the invention are stored;

FIG. 2 represents a perspective view of the interior of a case according to the invention;

FIG. 3 represents an exploded perspective view of a cooling system according to the invention;

FIG. 4 represents a perspective view of a second embodiment of a case according to the invention;

FIG. 5 represents a perspective view of another embodiment of a case according to the invention in which the cooling system is linked to an external air extraction system; and

FIG. 6 represents a perspective view of a storage system in which a number of cases according to another embodiment of the invention are stored.

FIG. 1 schematically represents a storage system 1. A certain number of cases 2 are stored in the storage system 1 for electronic systems placed in cases 2, The cases 2 are held by rails 3 represented by solid lines and which form a rack. The storage system 1 can be a cabinet and can contain a number of levels similar to the one represented in FIG. 1, The storage system may also be tilted in order to accommodate cases 2 stored horizontally.

Each case 2 can be handled and removed from the rack by means of a handle 4. A first opening 5 is represented on the accessible face or front face of the case 2. This first opening 5 includes a grille 6.

The case 2 is metallic, the electronic systems intended to be inserted inside this case 2 are therefore protected against the electromagnetic interference emitted and received.

FIG. 2 shows the interior of a case 2. The metallic frame of this case 2 is not represented in this figure. Likewise, the grille 6 is not represented, and the opening 5 can be seen. A second opening 7 is situated on the face opposite to the face in which the first opening 5 is situated.

A cooling system 8 comprising a duct 9 linking the openings 5 and 7 is arranged inside the case 2. This duct 9 is metallic, and its wall is air-tight.

A support 10, intended to receive an electronic system, is arranged on a wall of the case 2. This support 10 links the electronic system to the case 2 and makes it possible to dissipate the power lost by the electronic system.

The support 10 is metallic and therefore has a high thermal conductivity. The wall of the duct 9 of the cooling system 8 is linked to the support 10. Thus, there is a transfer of heat by conduction between the electronic system, its support 10 and the cooling system 8.

FIG. 3 shows the interior of a cooling system 8. Two fans 11 and 12 are arranged at the ends of the cooling system 8. The fans 11 and 12 are respectively associated with the openings 5 and 7.

The control means for these fans 11 and 12 are independent. A failure of the electrical power supply of one of the two fans 11 or 12 does therefore not result in the other fan 11 or 12 being stopped. The cooling system 8 is therefore robust to a failure of one of the two fans 11 or 12.

Thermal dissipation fins 13 are arranged inside the cooling system between the fans 11 and 12. The heat transferred by conduction through the support 10 and the duct 7 is then dissipated in the fins 13. A transfer by convection makes it possible to cool these fins 13 and the case 2 as a whole, by making a flow of air circulate in the cooling system 8, by using the fans 11 and 12.

In the event of a failure of the electronic system included in the case 2, a fire may start. The cooling system 8, which uses cooling by forced convection, cannot provide oxygen to this burning electronic system. Furthermore, the flames are contained within the case 2.

The invention is not limited to the embodiment described previously with reference to FIGS. 1, 2 and 3.

Referring to FIGS. 4 to 6, in which elements that are identical to those described with reference to FIGS. 1, 2 and 3 are given the same numerical references, the arrangement of the cooling system can be altered and other elements can be added.

For example, as can be seen in FIG. 4, the front face of the case 2 includes a second opening 5 equipped with a second grille 6. The case therefore has two cooling systems 8 and two ducts 9 passing through it. The effectiveness of the cooling is therefore enhanced.

In the embodiment of FIG. 5, the second opening 7 of the case is linked to an external air extraction system 14. This air extraction system comprises a first duct 15 linked to the opening 7. A second duct 16 is connected to the first duct 15. The second duct 16 can extract the hot air from the case 2 and the hot air from the adjacent cases 2. The air extraction system 14 can also make it possible not to discharge the hot air directly into the air around the case 2.

According to yet another embodiment illustrated in FIG. 6, the opening 5 is situated on the top face of the case 2. The opening 7, not represented, is situated on the bottom face of the ease. The cooling system, which is vertical, does not discharge air onto faces facing a face of another case 2.

Advantageously, the flow of air passing through the cooling system 8 can circulate from the first opening 5 to the second opening 7 or from the second opening 7 to the first opening 5.

It will be noted that these various embodiments can also be combined.

The invention affords the benefit of a device for protecting an electronic system that is suitable for containing the smoke inside the device and for preventing the provision of oxygen in the event of a fire starting.

There is also the benefit of a cooling system that is stand-alone and robust to the failure of a fan.

The case obtained also makes it possible to protect the contained electronic systems against the electromagnetic interference emitted and received. 

1. Device for protecting an electronic system, comprising a case (2) intended to receive the electronic system and to be mounted in a rack (3) of a storage system (1) that can receive a number of cases (2), said case (2) comprising a first opening (5) situated on a first of its faces, a second opening (7) on a second of its faces, and a cooling system (8) comprising a duct (9) linking the openings (5, 7), characterized in that the wall of the duct (9) is air-tight.
 2. Device according to claim 1, characterized in that the case is metallic.
 3. Device according to one of claims 1 or 2, characterized in that the cooling system (8) includes a first fan (11) associated with the first opening (5) and a second fan (12) associated with the second opening (7).
 4. Device according to claim 3, characterized in that the cooling system (8) includes heat dissipation means (13) situated between the first fan (11) and the second fan (12).
 5. Device according to one of claims 1 to 4, characterized in that the electronic system is linked to the case (2) by a support (10) suitable for dissipating the power lost by the electronic system.
 6. Device according to any one of the preceding claims, characterized in that the cooling system (8) is linked to an external air extraction system (14).
 7. Device according to any one of the preceding claims, characterized in that the flow of air passing through the cooling system (8) circulates from the first opening (5) to the second opening (7) or from the second opening (7) to the first opening (5).
 8. Device according to any one of the preceding claims, characterized in that said first face is the accessible face of the case (2), or front face, and said second face is the rear face of the case (2).
 9. Device according to one of claims 1 to 6, characterized in that said first face is the bottom face of the case (2) and said second face is the top face of the case (2).
 10. Device according to any one of the preceding claims, characterized in that it comprises, on said first face two openings (5), on said second face two openings (7), two cooling systems (8) each comprising a duct (9) linking the openings (5) of the first face to the openings (7) of the second face. 